Okay, so they’re not exactly cutting edge. But landscapers in Colorado digging a hole for a fish pond in the front yard of a Boulder home last May stumbled onto a cache of old tools—ones that turned out to be 13,000 years old, according to the Associated Press.

The 83 ancient stone tools are believed to have been buried by the Clovis people, ice age hunter-gatherers who remain a puzzle to anthropologists, the report said. The home’s owner even thought they were just a century or two old, but contacted researchers at the University of Colorado just to be sure. The tools are among just a handful found in North America.

So far, researchers determined via biochemical analysis of protein and blood residue on the tools that they were used to kill camels, sheep, horses, and bears. The owner of the house plans to donate most of the tools to a museum, but bury a few back in his yard so that they “stay where they belong,” according to the report.